At the same time that I purchased the Thermal Hopper from the other thread, I had the opportunity to rescue this poor TD .020. It was in the original blister pack which excited me to no end since I had never had one of those boxes, but the poor engine was in terrible shape when I got it home. The tank was rotted worse than any I had ever seen and the carb body disentegrated as soon as I tried to remove it from the engine. No problem since I had some replacement plastics on hand. Turns out that the crank was seized in the case! I soaked it in oil, baked it, torched it, tried to tap it out with a hammer, etc with no luck. I reluctantly resorted to putting pliars on the prop driver, mauling it as I went. The splined teeth stripped smooth on the crank! Finally, I gripped the crank spline in some needle nose and with constantly applied heat and force, it finally broke free. The crank was toast. Turns out that the piston also was seized in the cylinder, causing me to recreate much of the same grunting noises to get it free. Seems someone had previously burred the cylinder(probably with the Cox tool) as is a common occurance. I ordered some new shiny bits such as prop driver from Cox Int and a crankshaft from EX Model Engines. When I get it all reassembled, it's going to get one of those awesome aluminum backplates for sale over at the RC Groups 1/2A forum. Since I had already recently refurbished a couple of TDs with new plastic bits and such, I put one of those in the display box. I ended up with a neat display for one of my refurbished engines and another old neglected TD .020 is getting the attention it deserves and will soon be breathing fire once again. Fun stuff!

hello Tee Bee, the way it looks, it is possible that someone has used gasoline to wash the engine, you may have dipped it in gasoline. I do not see any other way for it to become rotten by nature like that.It is (I think) that the plastic was altered by some cleaning element used by another previous owner.

Tank rot is caused by the chlorine in the PVC tubing leaching out and damaging the Delrin tank. This is why it always rots out by the fuel nipple on the tank. Store your plastic tanked TDs without the fuel line connected to the tank.

This is very interesting, but I do not understand something ...When I translate to my language, I read that chlorine damages plastic, what I do not understand is, where it is produced or where chlorine exists?The original hose of the engine produces that effect ?.I would like to understand this topic well.Thank you

I do not think that extensive tank rot as seen in the pictures was just because of the plastic fuel tube, that we know often caused rotting but only around the fuel nipple area...after the nipple has rotten away, and direct contact with the plastic tube was detached,what would have continued the rotting into almost half of the tank?

Maybe the previous owner - who may not have been a prudent and cautious one, also burring the cylinder - may have experimented with a flammable material for fuel, that was incompatible with the delrin tank material? Maybe common gasoline, acetone, or similar?

Mauricio I read somewhere that the stock fuel tube put on TD-s in the factory had chlorine emitted when ageing, and that was detrimental to the delrin material...but to such an extent as seen here????

balogh wrote:I do not think that extensive tank rot as seen in the pictures was just because of the plastic fuel tube, that we know often caused rotting but only around the fuel nipple area...after the nipple has rotten away, and direct contact with the plastic tube was detached,what would have continued the rotting into almost half of the tank?

Maybe the previous owner - who may not have been a prudent and cautious one, also burring the cylinder - may have experimented with a flammable material for fuel, that was incompatible with the delrin tank material? Maybe common gasoline, acetone, or similar?

Mauricio I read somewhere that the stock fuel tube put on TD-s in the factory had chlorine emitted when ageing, and that wasdetrimental to the delrin material...but to such an extent as seen here????

Ahhh now I understand András, the tube itself generates chlorine over time and that affects the nipple of the tank basically. That is what I learned now.Now judging by the comment of Tee Bee and observing the engine, where the Carb Body is even shrunk, I think that that could never have made the effect of the original hose, it is too much. I tend to think, as I mentioned earlier, that some previous user, I try to clean the engine with some agent that attacked the plastic.It is possible that there is the sum of situations, but I argue that the Carb Body, is very extropeado to think about the effect of the original hose of the engine. At least it's my opinion.I have marked with colored arrows what I think is related:Yellow arrow: it may be the cause of the chlorine generated by the original engine tube (according to comments)Green Arrow: In my opinion and according to my experience, that hose appears to have been attacked with gasoline, given its color and apparent crystallization.Celestial arrows: here you see the carb body totally attacked and even shrunk, I think something outside could have done that damage so important.It is good to be able to determine the real causes of the damage, in order to avoid unnecessary worries.Thank you András for your clarification.

I'm sure a six hour boil in anti freeze would have loosened your TD's engine components sufficiently to separate them without resorting to pliers. But by doing so the quality of the anodized parts would be compromised.

Yeah, I keep an old crock pot of antifreeze for old glow engine projects but elected to sacrifice the crankshaft and prop driver instead of losing the case anodizing. Matt at EX has new cranks to sell and needs me to keep sending a steady supply of my dollars.

rsv1cox wrote:I'm sure a six hour boil in anti freeze would have loosened your TD's engine components sufficiently to separate them without resorting to pliers. But by doing so the quality of the anodized parts would be compromised.

Either way Mauricico your engine turned out great.

Bob

Hello Bob! .... the engine is not mine, it's from Tee Bee, it looks like new thanks to his work done on it!

rsv1cox wrote:I'm sure a six hour boil in anti freeze would have loosened your TD's engine components sufficiently to separate them without resorting to pliers. But by doing so the quality of the anodized parts would be compromised.

Either way Mauricico your engine turned out great.

Bob

Hello Bob! .... the engine is not mine, it's from Tee Bee, it looks like new thanks to his work done on it!

My mistake Mauricio, I even spelled your name wrong.... ....I meant to type Tee Dee. I must have had you on my mind.

Tee Bee wrote:Yeah, I keep an old crock pot of antifreeze for old glow engine projects but elected to sacrifice the crankshaft and prop driver instead of losing the case anodizing. Matt at EX has new cranks to sell and needs me to keep sending a steady supply of my dollars.

I'm joining you in that effort. I'm running a tab there trying to complete a bunch of "parts" Cox engines.

rsv1cox wrote:I'm sure a six hour boil in anti freeze would have loosened your TD's engine components sufficiently to separate them without resorting to pliers. But by doing so the quality of the anodized parts would be compromised.

Either way Mauricico your engine turned out great.

Bob

Hello Bob! .... the engine is not mine, it's from Tee Bee, it looks like new thanks to his work done on it!

My mistake Mauricio, I even spelled your name wrong.... ....I meant to type Tee Dee. I must have had you on my mind.

Bob

Hey Bob, there is no problem, the way of writing names in another language is complicated, even I am helped by a translator to be here, so I always say, I hope you can convey what I really want to say!If you have me in mind, that's good, it's good for people to have it in mind!